Kremper and Wilster Marsch, the marshy region to the right of the lower Elbe near the villages of Krempe and Wilster; the nearest city is Gluckstadt, West Prussia, Germany. In the middle of the 16th century Mennonites were already located in the "royal wilderness." The pastor of Wilster requested the king to watch the "Hollanders" suspected of Anabaptism. Nevertheless they established themselves in such numbers that they brought about a change in agriculture from mere cattle raising to dairying that gradually spread to the east coast of Holstein. Great quantities of cheese were shipped to Lübeck around 1600.

Gradually sharper measures were taken against the Mennonites. The provost of Itzehoe complained in 1635 about the great "applausum" they were winning, and ordered that citizens who had given the oath of loyalty to state and church should see to it that none charged with false doctrine stayed in the parishes. Christian IV decided that the "Manists" should cease their "exercise of baptism and other ceremonies" and "turn to our religion," or leave the country. The alarmed immigrants claimed the (see Glückstadt) Privilegium of 1631, asking for three years' grace on account of flood damage and the building of expensive dikes. This request was refused. But by 1642 it was again reported that Mennonites had again entered the country, and were ordered out of the Steinburg district within four weeks. In August 1643 Christian IV again directed the authorities to "keep a watchful eye on sects like Anabaptists, Mennonites, and others in the marshes." Now it became quiet. Most of them likely took refuge in Glückstadt.

A possible attempt to settle in the adjacent Süderdiethmarschen is inferred from a prohibition of such settlement issued by the king in 1637.

They were more leniently treated in the parishes of Brockdorf and Wewelsfleth, where a Mennonite applied for a teaching position. These two parishes belonged to the same district (Steinburg) as the Kremper and Wilster Marsch.